Method and means for forming stacked magnetic cores



Jan. 10, 1950 v A. F. MITTERMAIER 2,494,349

METHOD AND MEANS FOR FORMING STACKED MAGNETIC CORES Filed Aug. 21, 1946 4 Sheets-Sheet l Figl Inventor: Armin F M ittermaie'r,

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Jan. 10, 1950 A. F. MITTERMAIER 4 us'mon AND MEANS FOR FORIIING STACKED MAGNETIC CORES 4 Sheefc's-Sheet 2 Filed Aug. 21, 1946 Inventor- Ar-rnin E Mitter-maier, by f a W a a a His Attorney Jan. 10, 1950 A. F. MITTERMAIER 2,494,349

METH D AND MEANS FOR FORMING STACKED MAGNETIC conns Filed Aug. 21, 1946 4 Shasta-Sheet s Inventor: Armin FT Mithermaier,

HisAtMT-Be r Filed Aug, 21, 1946 Jan. 10, 1950 A. F. MITTERMAIER 2,494,349

' METHOD AND ms FOR FORMING STACKED MAGNETIC comes 4 Sheets-Sheet 4.

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Inventor: A -inf. Mittermaiefi Wan:

H is Attorney Patented Jan. 10, 1956 METHOD AND MEANS FOR FORMING STACKED MAGNETIC CORES Armin 1F. Mittermaier, Fort Wayne, Ind., assignor to General Electric Company, a. corporation of New York Application August 21, 1946, Serial No. 692,098

7 Claims. i

This invention relates to electric induction apparatus, particularly to improvements in stacked core type induction apparatus and to a novel method and means for making such apparatus.

A conventional type of stacked magnetic core for induction apparatus, such as transformers and reactors, comprises contiguous alternately reversed lamination layers, each containing an hshaped punching and an I-shaped punching located across the ends of the legs of the E-shaped punching. The reversal of the punchings in alternate layers causes the butt joints between the punchings in each layer to be bridged or overlapped by adjacent layers so that the core joints are lapped. Heretofore, such cores have been stacked into the window of a conductive winding or coil by hand.

In accordance with this invention I provide a novel automatic machine for relatively quickly stacking a core having two dissimilar punchings per layer with the punchings reversed in alternate layers. However certain novel features of my machine, such as those for handling bent or warped punchings, are not limited to any particular type of core or shape of punchings and therefore my machine in its broader aspects is not limited to stacking two different punchings per layer.

In practicing my invention 1' provide a novel core clamp for not only holding the laminations firmly in place but also guiding the liminations in the proper direction as they are stacked into coils and insuring that the coil window is of suflicient size readily to receive the laminations.

An object of the invention is to provide a new and improved electric induction apparatus.

Another object of the invention is to provide a new and improved core clamp.

A further object of the invention is to provide a new and improved core stacking machine.

A further object of the invention is to provide a new and improved method of making electric induction apparatus.

The invention will be better understood from the following description taken in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

In the drawings Fig. 1 is a side elevation view of a machine embodying my invention, Fig. 2 is a perspective view of an electric induction apparatus made in accordance with my invention, Fig.

3 is a perspective view illustrating the details of a form of core clamp embodied in my invention and showing how the clamp is placed in a conductive winding. Fig. 4 is a sectional view taken on line 4-4 of Fig. 2, Fig. 5 is an enlarged partly broken away, partly exploded perspective view of the upper portion of the machine shown in Fig. 1, Fig. 6 is an enlarged detailed view of a part of the mechanism shown in Fig. 5, Fig. l is a still further enlarged perspective view of the central portion of the mechanism shown in Fig. 5, Fig. 8 is a still further enlarged longitudinal sectional view of the central portion of the machine taken on line 88 of Fig. 5, Fig. 9 shows the mechanism of Fig. 8 in a diiferent operating position,- Fig. 10 is a detailed view showing the mechanism in another position, and Fig. 11 is a circuit diagram.

Referring now to the drawing and more particularly to Fig. '1, a table top 9 is supported by legs 2 on a base 3. The driving elements for the machine shown in Fig. i are mounted below the table top land are designated generally by t and the material which is operated on by the machine and the parts of the machine which operate on this material are mounted above the table top I and are indicated generally by ii. The driving elements 4 in turn consist of a power assembly 6 shown mounted on the base It and a cam shaft 7 which is shown journaled in brackets 8 depending from the under side of the table 5. The power assembly comprises an electric motor is which drives a sprocket l0 through a speed reducing gear box it and a clutch l2 which is operated by a solenoid I3. At the right-hand end of the cam shaft 7 is a sprocket M which is driven from the sprocket ill by a chain i5. Positive and rapid stopping of the cam shaft '1 is obtained by a brake mechanism' H5 at the left-hand end of the cam shaft! and this brake is controlled by a solenoid I! through a suitable linkage l8.

lhe assemblies 5 and l are generally symmetrical with respect to an imaginary vertical center line drawn through the table 8. Thus, the mechanism 5 includes a right-hand magazine is for core punchings and a complementary lefthand magazine it. Each is a double magazine containing E punchings 28 on the outside and I punchings M on the inside. Also, there are right-hand and left-hand horizontally reciprocating members which are driven respectively by cam followers 22 and 22' which are set into the respective grooves of scroll cams 23 and 23' on the cam shaft 1. The cams 23 and 23' are duplicates but they are mounted with a relative angular displacement of 180 degrees so that the back of cam 23 looks like the visible portion of cam 23 and the back portion of cam 23 looks like the visible portion of cam 23'.

The reciprocating assemblies which are driven by the cams 23 and 23' through the followers 22 and 22' are for the purpose of pushing the laminations from the magazines toward the center of the assembly so as to form a stacked core 24 for a coil 25.

Before describing in detail how the horizontally reciprocating mechanisms operate on the various laminations so as to form the core 24 I will first describe in general terms the major cycle of operation of the machine. It will be observed that both cam followers 22 and 22' are in their extreme right-hand positions. Assume now that the cams 23 and 23' are rotating in the direction of the arrows marked thereon. During the first half revolution of the cam shaft 1 cam follower 22 will make a long stroke to the left and in so doing will insert one E punching from the magazine l9 into the core 24. It will then be withdrawn partway to the right. During this same half revolution cam'follower 22' will make a short horizontal return movement to the left and then a similar movement to the right during which an I punching 2| from the magazine I9 is inserted in the core 24. During the next half revolution of the cam shaft I the cam 23 causes an I punching 2| from the magazine l3 to be inserted from right to left in the core and the cam 23 causes an E punching 20 from the magazine l9 to be inserted from left to right in the core 24. This completes one cycle of operation and this cycle is repeated until the core is stacked. to the proper height.

It will be observed that in the above-described cycle of operation the cam followers 22 and 22 move simultaneously to the left and then simultaneously to the right. However, that is not an essential feature of the operation and by merely rotating one of the cams 23 or 23 ninety degrees on the cam shaft I relative to the other cam the operation will be such that both followers 22 and 22' move inwardly simultaneously and then move outwardly simultaneously. In that case an E punching will be inserted from the right-hand side of the core simultaneously with the insertion of an I punching from the lefthand side of the core and this will be followed in the next half cycle of operation by the simultaneous insertion of an E punching from the lefthand side of the core and an I punching from the right-hand side of the core, thus completing the cycle of operation.

As has already been noted, the I punchings are in the parts of the magazines which are nearest the center and in order to get the lowermost I punching in each magazine out of the way when it is necessary to slide an E punching into the core additional cams 26 and 26' operate on push rods or raising members 21 for the I punchings.

The coil is mounted in the machine in a sliding carriage 28 which is movable perpendicular to the plane of the drawing for, among other things, facilitating insertion of the coil 25 and the removal of the completed core and coil assembly. An electrical interlock for the circuit 4 of the clutch I2 and brake I8 is provided in the form of a switchette 23 which through a suitable operating member 30 is closed only when the transversely movable carriage 28 is in its proper position. The machine is automatically stopped when the core 24 is stacked to the proper height by means of a limit switch in the form of a switchette 3| which is actuated by a rod 32 which is attached to a yoke member 33 which during the operation of the machine rests on the top of the core 24 so that it is raised step by step as the height of the core builds up. The yoke 33 is shown raised in its releasing position by means 0! a cam 34 operated by a handle 35. These parts are journaled in a cross bar 35 attached to the brackets 8 and the cam 34 actuates a tie member 31 which runs between the rod 32 and a complementary rod 32 which is not visible in Fig. 1. By means of the handle 35 the yoke 33 can be lifted out of the way so that the carriage 28 can be slid transversely for removing a completed core and coil assembly.

Laminations of the core are held together by a spring clamp member 38 and this member also very materially co-operates with the operation of the machine in a manner to be described hereinafter.

A completed core and coil assembly is shown in Fig. 2. I This figure clearly shows how the lamination layers are reversed so that the joint between the E punchings 20 and the I punchings 2| are staggered or overlapped. In Fig. 3 a coil 25 is shown with one clamp 38 in place and an other one outside of the coil window. Each clamp has a specially formed center section 33 which is slightly wider than the width of the center leg of the E punchings. This is for the purpose of spreading the window of the coil 25 in case the latter is too small so that the center legs of the E punchings will readily pass through the coil window. At each end of the clamp 33 is a wider extension 40, one of which presses against an E punching and the other of which presses against an I punching so as to hold the two punchings in an outer layer of the core together. The core clamp 38 is notched at 4| in the corners between the parts 39 and 40 in order to prevent it from cutting into the insulation forming the coil window at the corners thereof. A central ridge 42 in each core clamp extends toward the center of the coil window and is engaged by the outer lamination layer and pressed outwardly, thus flexing the clamp 38 so that its ends effectively pivot about the sides of the coil window, thus forcing the wings or extensions 40 toward each other and toward the core so as to firmly clamp the E and I punchings in the outer layers of the core. This action is clearly shown in Fig. 4.

In Fig. 5 the right-hand side of the machine has been shown with parts broken away and exploded. Thus, the magazine I9 has been raised from the table I so as to show the parts of the machine which are normally underneath it, while the complementary magazine I9 is shown in its installed position. The transverse carriage 28 moves in a transverse slot 43 in the table it being provided with an operating handle 44 at each end and its motion at each end being limited by a stop screw 45. As shown, it is provided with lower side ridges 45 which slide in slots 47 so that any vertical movement is prevented. The carriage 28 is shown as having two coil receiving wells 48, the right-hand one of which is shown as containing the coil 25, and

two clamps 38 which are installed face to face in the same relative positions they have in Fig. 2, 3 and 4 but they are pushed together and are at the top of the coil window as the coil has been pushed as far as it can into the right-hand well 48. During the operation of the machine an operator can place a secondcoil in the left-hand well 48 while the machine is stacking a core in the coil 23 so that as soon as the machine stops n the completion of the core the handle 35 can be operated to raise the yoke 33 whereupon the carriage 28 can be pushed to the right, the lever 35 operated to lower the yoke 33 and the machine restarted and then the completed core and coil assembly can be removed from the right-hand well and this operation repeated.

The carriage 28 is also shown as being provided with indentations 49, only one of which is visible, which cooperate with the plunger 30 for operating the interlock switch 29 so that this switchwill only be closed when the carriage 28 is in one end position of its travel or the other one.

In Fig. the cam 34 has been rotated so as to lower the cross member 31 to its lowermost position so as to provide maximum space between an operating plunger 50 for the limit switchette 3| and a weight 5| which slides 'between supporting plates 52. The vertical position of the weight is adjustable by meansof a set screw 53. In operation a cross arm which carries the yoke 33 and which corresponds to the cross member 31 is attached to the ends of the vertical rods 32 by means of studs 54 and cushioning springs 55. The flat bottom surfaces 530i the yoke member 33 initially rest on fiat raised pads or gauging surfaces 51 at each end of the wells 48 and as the E punchings are fed into the core their outer legs move between the surfaces 56 and 51, thus raising the yoke 33. The yoke is held down relatively firmly by means of weights 58 on the rods 32 and the coil 25 is always pressed down by means of a spring plate 59 in the yoke 33. When the core is completed the limit switch 3| will be raised until its operating projection 50 encounters the weight 5| whereupon the switch 3| willopen. The reason the weight Si is slidable is so as to allow the are fed in at the same low level as the E punchwardly by a spring 85 and the upward movement is limited by a nut 86. The downward movement of the part 64 is limited by an adjustable set screw 81 in a cross member 68 which runs transversely underneath the table I.

Referring now to Fig. 7 which shows the principal operating parts or the right-hand half of the machine at the top of the table I in enlarged form, an E punching 20 is shown in contact with the ends of the pushers 62 in position for being moved toward the coil 25 and into its window between the two clamps 38. This single punching 20 is shown directly below a stack of punchings 23 and this stack is directly below a space 63 in the magazine l9. This space has outside dimensions corresponding to those of the punchings 20 and has two rectangular members 10 extending vertically within it, which members fit into the spaces between the center and the two outer legs of the E punchings; The edges ll of the members I3 are gauging edges for the Es; that is to say, they hold back all of the Es in the magazine except the lowermost one which can drop down below the gauging edges ll far enough so that it can be pushed toward the well 25 by the pushers 62.

Next to the stack of E punchings 20 is a stack of I punchings 2| which is vertically below a rectangular slot 12 in the bottom of the magazine l9. This slot is the bottom opening of the portion of the magazine I!) which contains the I punchings 2|. The square edged portions 13 on the side of the slot 12 toward the coil 25 are gauging edges for the Is and serve the same purpose for the PS that the edges II on the members 10 do for the Es.

For preventing jamming of the Es in case one or more of their legs should be warped upwardly,

4 the portions of the edge of the I slot 12 which are cam to raise the yoke up off the completed core and coil sufficiently to allow the carriage 28 to be moved transversely for bringing a new coil into position and for allowing removal of the finished core and coil assembly.

The follower 22 of the cam 23 terminates in a head portion 60 which is firmly fastened to a pusher member Bl having divided pusher fingers 62. The assembly BI is confined by guides 63 so that it can only slide back and forth in a straight line. The ends of the pusher fingers 62 are what push the laminations into the core. Their top end edges are slightly rounded to prevent picking up two punchings in case the latter are under size as of thickness or are bowed.

For accurately positioning the coil window in the machine each side of each of the wells 48 is provided with two projecting members 64. The facing or inner vertical sides of these members engage the sides of the extensions of the core clamps 38 and thus accurately orient the core window in the machine. Another function of the parts 64 is to raise the PS into the plane of the last inserted Es during the automatic stacking operation. It is therefore necessary that their top surfaces should be normally flush with top surfaces of the pads 51. The top surfaces of parts 64 are therefore gauging surfaces for the 1's. In order to absorb the shock when the I punchings encountered by the ends of the legs of the Es are chamfered or beveled at the three places designated by the numeral 14.

In order that the E-shaped punchings may get past the stack of I-shaped punchings the latter rest on inwardly extending surfaces on vertically movable rods 15 which pass through the table I and which are actuated by the cam 26 through the cam follower assembly 21 which is shown in most E punching 20 rests on a fixed surface 18.

The front or leg ends of the E punchings are tilted downwardly as they are slid into the core by three chamfered projections 88 on a pivotallymounted U-shaped member 8|. The complementary part 8| for the left-hand magazine assembly shows the shape of this member when viewed in the opposite direction and the arms of the U are indicated at 82 as being pivoted to a fixed block 83' by pins 84'. The yoke part of the member 8| is urged downwardly by the end of a spring clip 85 which is fastened in the block 83'.

The core as it is built up is kept from moving back and forth under the impact of the successive insertion of punchings from opposite directions by means of hold-back dogs 88, the complementary ones of which on the left-hand side are designated by 86'. Each punching as it is inserted in the core can slide under the bottom of the hold-back dogs as they are vertically slidable in slots in supporting blocks 81' and are urged downwardly by springs 88'.

Fig. 8 is an enlarged vertical section through the table top on the line 8-8 of Fig. 5 and shows the parts in essentially the same relative positions which they occupy in Figs. 1, 5 and 7.

For insuring that the back or yoke side of the lowermost E punching will be engaged by the ends of the pushers 62 the front of the stack of E punchings 28 is raised by a spring-biased detent 89 which is set into central fixed member 18. This tilts the entire stack of E punchings slightly upward at the front so as to be sure that the back edge is down. Detent 89 could obviously also be cam operative if desired.

The detailed mechanical operation of the machine can best be understood by reference to Figs. 8, 9 and 10. In Fig. 8 the pushers 82 and 82' have not quite completed their movement to the right. The pusher 62 is finishing the insertion of an E punching 28 into the core immediately above the bottom clamp 38. The raising rod I5 for the left-hand stack of I punchings has moved down but the bottommost I punching 2| and E punching 28 in the left-hand magazine l9 rest on the top surfaces of the pushers 62' and therefore cannot fall any further. The movement of the pushers 62' and B2 to the right will continue until the punching 28 has been pushed all the way into the core so that its end butts up against the side of the I punching 2|. which is already in place in the same layer. The spring bracket 85 allows the part 8| to move upwardly out of the way of the pusher 62' so that its stroke can be completed. It will be noted that in the closing stages of the insertion of the E punching 28 it is tilted up at the front and down at the back by means of the member 8| so that the front edges of the outer legs of the E punching will ride up over the chamfered edges of the gauging surfaces 51 which are shown most clearly in Fig. 7. It is the vertical distance between the surfaces 51 and the surfaces 56 on the member 33 which is the measure of the Stack height of the core and eventually causes automatic stopping of the machine by the operation of the limit switch 3|.

It will be observed in Fig. 8 that the lowermost I punching 2| in the core is being held up by the members 64 so that there is a ga between the clamping extension 48 on the bottom core clamp 38 and the lowermost I punching 2| and it is into this space that the next E punching will be pushed from right to left by the pusher 62.

The forcing of the lowermost E punching 28 into the core by the pusher 62 tends to move the entire core from left to right and this movement is effectively prevented and the right-hand edges of the punchings are smoothly aligned by means of the hold-back dogs 88.

In Fig. 9 the cycle has progressed until the pushers 62 have moved sufficiently to the left so that they are Just about to insert an E punching 28 into the core from right to left. The gauging edges II which are shown inFig. 7 have prevented all but the lowermost punching 20 in the magazine I9 from being picked up by the pushers 62. In the position shown in Fig. 9 the front edge of the E punching 28 is tilted downwardly by the member 8| and the hold-back dogs 88 and the back of the punching 28 is raised by the spring-biased detent members 18. This is for the purpose of insuring that the ends of the legs of the E punchings will not catch on the lower righthand corner of the core stack and any of the legs which tend to be warped upwardly will be bent down by the deflecting surfaces 80 on the member 8|. The ends of the legs of the E punching 20 strike the outwardly flared tips 88 of the clamp 38 and are thus deflected upwardly toward the core stack. The punching 28 continues on from right to left with the same general amount of tilt until the ends of the legs strike the crinkle II in the core clamp 38. This crinkle is slightly in toward the center from the butt joint between the Es and PS.

The purpose of continuing to push the punching 20 in on the angle shown in Fig. 9 is to prevent the ends of its legs from catching on the ends of the legs of the E punching in the layer above in case there is any downward warpage of those legs. This is illustrated in Fig. 10 where one of the legs of the E punching 28 in the layer above projects downward slightly at 92. By means of the tilt of the right-hand punching 2| and the position of the crinkle 9| it will be seen that the ends of the legs of the right-hand punching 28 can readily slide under the joint between the punchings in the layer immediately above. From then on as the punching 20 is fed into the core the clamp 38 levels it off so that it eventually is pushed all the way into the core in a manner illustrated by the left-hand half of Fig. 8.

As the machine continues to operate, the lefthand pusher 62 will move part way to the left so as to permit an I punching 2| to drop down but it does not move far enough to the left to permit an E punching 20 to drop down before the motion of the pusher 62 is reversed. In this manner an I punching is picked up and it is forced into the core in very much the same manner as the E punching except that as it does not have to slide under the joints between the punchings in the layer above it, it is not necessary to have it tilted in the same manner that the E punchings were tilted. The front edge of the I punching strikes the chamfered surfaces of the member 64 and thus is raised upwardly suiliciently to allow the next E punching from that side of the machine to be inserted under it.

It might be supposed that by extending the gauging surfaces 51 to the right and left an amount equal to the depth of the members 64 the latter could be dispensed with because then the ends of the I punchings would be raised on the surfaces 51. However, that cannot be done because the ends of the surfaces 51 would then prevent the downward tilting of the E punchings 20 so as to obtain the action illustrated in Fig. 10.

It will be observed from Figs. 5, 7, 8 and 9 that the core is stacked downwardly from top to bottom; that is to say, the ilrst laminations are inserted between the two clamps 38 which are in contact with each other at the top of the coil window and the latter is pressed all the way down into the well 48 of the transverse carriage 28 and as each successive layer is inserted the coil rises up out of the well 48. However this is not essential. For example the clamps 38 and coil 25 could be in the positions shown in Fig. 8 at the start of the stacking operation, it being understood that then no punchings would be between the clamps. As the punchings are fed in the core stack would build up from the middle to the top until the first layer came in contact with the top clamp 38. The action would then continue as already described. Of course the stacking could also start at the bottom of the coil window if the coil were raised all the way up at the start.

The only purpose of the top clamp 38 is to hold the top I punching in place and therefore it can be omitted when the top layer has only one punching, such as an E punching. The ends 40 of the clamps 38 may also be extended beyond the core if desired and those extensions used for attachingthe core to some other apparatus, such as another core.

A suitable electric circuit for the machine is illustrated in Fig. 11. As shown, the motor 9 may be connected to any suitable supply circuit 83 by means of a main power switch 94. The

starting of the machine is controlled by eitherof two parallel connected push buttons 95 which may be located on opposite sides of the machine near the handles 44 for the transverse carriage 28. However, the machine must be in proper condition for starting. One condition is that the transverse carriage 28 be in one extreme position or the other and, as shown, the carriage 28 has depressions ts which co-operate with a plunger so for actuating an interlock switch 29 so that the latter will only be closed when the carriage 23 is in one extreme position or the other and this switch will be opened at all other times.

Another condition is that the limit switch 3i be closed indicating that the machine does not contain a completed core into which additional punchings could not be forced. However, as the rod 32 carrying the limit switch 3i is raised upwardly each time the first punching of a layer is inserted in the core regardless of whether this is an E punching or an I punching the limit switch 3i will operate to stop the machine before the last layer is completed by the insertion oi the second punching in that layer. In order to prevent such premature stopping of the machine an auxiliary switch to is connected electrically in parallel with the limit switch 3i and is operated by a cam QT! on the cam shaft l. The switch only opens when the cams reach the position shown in Fig. l or a position representing onehalf a revolution therefrom as only in those two positions of the cams will a lamination layer have just been completed.

A relay 38 is interposed between the main con trol. circuit of the push buttons 935 and the circuits for the solenoids i3 and ll. This relay has an operating coil 99 which is connected in a circuit from the left-hand side of the supply circuit 93 through either push button 95, through the interlock switch 29 and either limit switch 3! or auxiliary 96 and back to the other side of the main supply circuit through a conductor 100. The

hit

"10 relay 98 has a pair of normally open seal-in contacts llll which are connected in parallel with the push buttons 95 so that as soon as the relay 38 picks up, it seals itself in so that it is unnecessary to continue actuation of the push buttons 35 in order that the machine will continue to operate. The relay 98 has another set of normally open contacts I02 which serve to connect the brake releasing solenoid l1 directly across the supply circuit and this relay has a third normally open set of contacts I03 which serve to connect the clutch actuating solenoid I3 directly across the supply circuit. In this manner as soon as the relay 98 picks up the brake I6 is released and the clutch I2 is engaged, thus starting the machine and it will continue to operate until limit switch 31 and auxiliary switch 36 are open, switch 35 determining which is the last layer which will be inserted in a core and switch 96 continuing the operation until that layer is completed.

As soon as both switches 3i and 96 open the relay to drops out, thus immediately applying the brake it and stopping the cam shaft. At the same time, of course, the clutch I2 is released so that no power is applied to the cam shaft from the motor 9 but the clutch is so constructed that it will slip if the mechanism should jam during the stacking of a core.

The machine may also be stopped at any time merely by rotating the handle 35 so as to cause the cam 34 to raise the rods 32 and open the limit switch 3i.

While an automatic control for the machine has been illustrated in Fig. 11, it will of course be obvious that the cam shaft i can also be turned by hand in any simple manner such as by pro" viding it with a crank.

While there have been shown and described particular embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the invention and, therefore, it is aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an automatic corestaclring machine, a main supporting frame having a generally fiat normally horizontal top plate, an assembly sta tion near the center of said top plate, a pair of in-line slots in said plate on opposite sides oi said assembly station, a rotary cam shaft mounted beneath said plate in vertical alignment with said slots, means for drivingsaid cam shaft, a pair of reciprocatory lamination pushers slidably mounted on said top plate respectively above said slots, said pushers having elongated flat top surfaces parallel to said plate and having relatively sharp edges at their ends nearest said assembly station, a pair of scroll cams on said cam shaft respectively below said slots, cam followers em tending respectively through said slots for interconnecting each cam with the pusher above it, said cams having such a configuration so that for each revolution thereof their associated pushers go through a cycle which starting with a position nearest the assembly station comprises a short return stroke away from said assembly station followed by an equally short pushing stroke toward said station followed in turn by a long return stroke away from said assembly station and ending with an equally long pushing stroke toward said assembly station, a pair of dual magazines for core lamination punchings mounted vertically on said top plate respectively above said pushers, each magazine including a space for a stack of I-shape punchings and another space for a. stack of E-shape punchings, the bottom of each space for a stack of I-shape punchings being in vertical alignment with the end of the short return stroke of the pusher beneath it and the bottom of each space for a stack of E punchings being in vertical alignment with the end of the long stroke of the pusher which is beneath it, vertically movable rods extending through said top plate into the spaces for said stack of I punchings, and means including additional cams on said cam shaft for actuating said rods upwardly during the long pushing strokes of said pushers.

2. In a machine for automatically stacking a core in a conductive winding having a window, a base member, a magazine for a group of core punchings of one shape mounted on said base member, a second magazine for a group of core punchings of a different shape mounted on said base member, automatic means for stacking said punchings into a core at an assembly station, said means including apparatus for automatically sliding said punchings into said core from the same side thereof, a fixed stack height gauging surface contiguous to said assembly station for engaging only the punchings of one shape as they are first inserted into said core, and a second gauging surface contiguous to said assembly station for engaging the punchings of the other shape as they are first inserted into the core, one of said gauging surfaces being resiliently mounted.-

3. In an automatic core stacking machine, a base, a magazine for a group of core punchings of one shape mounted on said base, a second magazine for a group of core punchings of a different shape mounted on said base, means mounted on said base for automatically stacking said punchings into a core, said means including apparatus for automatically sliding said punchings into said core from the same side thereof, and additional means actuated by said apparatus for alternately raising and lowering the group of punchings of one shape so as to permit the alternate sliding of punchings of the other shape under the group of punchings of said one shape when it is raised.

4. In an automatic core stacking machine, a base, an assembly station on said base, a pair of magazines for differently shaped lamination punchings mounted on said base on opposite sides of said assembly station, means including a rotatable member for successively inserting punchings from said magazines into a core at said assembly station, a driving motor on said base, a clutch for connecting said motor to said rotatable member, a brake for stoppin said rotatable member, means including a manually controlled start mechanism for releasing said brake and engaging said clutch, an interlock mechanism for effectively incapacitating said start mechanism unless said rotatable member is in condition for operation, means including a limit switch for applying said brake and releasing said clutch when said core has been stacked to a predetermined height, an auxiliary mechanism for effectively incapacitating said limit switch until said machine completes the last lamination layer of said core.

5. In an automatic core stacking machine, a base, an assembly station on said base, a pair of magazines for differently shaped lamination punchings mounted on said base on different sides of said assembly station, means including a rotatable member for successively inserting punchings from said magazines into a core at said assembly station, a driving motor mounted on said base, a spring release electromagnetically engaged clutch for interconnecting said rotatable member and motor, a spring applied electromagnetically released brake for said rotatable member, a relay having an actuating coil and a plurality of normally open contacts, means for connecting certain of said contacts to said clutch and brake so that when said contacts are closed and said clutch is electromagnetically engaged and said brake is electromagnetically released, an energizing circuit for said actuating coil including a pair of manually operable push button start switches connected in parallel, an interlock switch in said circuit in series with said start switches, means for closing said interlock switch only when said rotatable member is in the proper operating position, a normallv closed limit switch in said circuit in series with said interlock switch, means for opening said limit switch when said machine has stacked a core to a predetermined height, an auxiliary switch in parallel with said limit switch, and means for opening said auxiliary switch only when all punchings comprising a lamination layer of said core are in place, and other of said normally open contacts being connected in parallel with said starting switches so as to act as seal-in contacts for said relay.

6. The method of stacking a core of interleaved E- and I-shaped punchings in the window of a conductive winding which comprises, providing a plurality of I-shaped punchings and a plurality of E-shaped punchings each of the latter of which has a central leg for insertion in said window, inserting in said window a pair of similar corrugated punching holders which are slightly wider than said central leg of said E-shaped punchings, inserting said central legs in said window alternately one punching at a time from opposite sides of said window between said punching holders whereby at least one of the latter is pushed step by step across said window ahead of the build-up of the core, and alternately inserting said I-shaped punchings in said core across the ends of the legs of said E-shaped punchings, said corrugated punching holders having an extended portion for engaging respectively the outermost of said I-shaped punchings.

7. In an automatic core stacking machine, a base, a reciprocatory pusher mounted on said base, a rotary cam shaft mounted on said base, driving means for said cam shaft, a cam on said shaft, means interconnecting said cam and said pusher for driving said pusher in a cycle which comprises a long pushing stroke and a short return stroke, a short pushing stroke and a long return stroke, a magazine for one kind of core punchings located above said pusher at the end of its long return stroke, a magazine for a different kind of core punching located above said pusher at the end of its short return stroke, said pusher on its long pushing stroke engaging a bottom lamination punching of one kind and said pusher on its short pushing stroke engaging a bottom lamination punching of another kind, a second cam on said cam shaft, and means 0perated by said second cam for raising the punch- I I 13 lugs 1n the lastqnentioned magazine during the long pushing stroke of said pusher.

ARMDIF.

nnmmcns crrEn UNITED STATES PATENTS Number Name Date Scott Nov. 28, 1893 .Fulton Dec. 8, 1925 Frank July 1, 1930 I Number 14 Name Date Ford Feb. 13, 1934 Granfleld Mar. 27, 1934 Bluzat July 17, 1934 Diersteln July 80, 1940 Joost Jan. 21, 1941 Jones Sept. 16, 1941 Putm'an Apr. 6, 1943 Mittermaier May 18, 1943 Mittermaler May 18, 1943 Kuperus Oct. 26. 1943 Schleicher Apr. 23, 1946 Galla. Dec. 2, 1947 

